Ella's first sentence

Just the other morning, I was getting Ella ready for school in her bedroom. When she was ready to go, we walked out of the room and Ella said "Papa, are you?" Unforunately, Papa was at work already, so we didn't get to find out where he was. But, we are considering that Ella's first official sentence. She uses it quite often now whenever she is looking for her mama or papa.